As is known in the art, a radio frequency (RF) circulator is typically a three-port device, having a first, a second, and a third port. A conventional circulator provides a directional capability, directing an RF signal applied as input to the first port to provide an output signal at only the second port. Similarly, the circulator directs an RF signal applied as input to the second port to provide an output signal at only the third port, and an RF signal applied as input to the third port to provide an output signal at only the first port.
A conventional circulator operates at a particular RF frequency or over a range of frequencies within which the circulation has an insertion loss characteristic and an isolation characteristic. It is generally desirable for the circulator to have a wide bandwidth, a relatively low insertion loss characteristic, and a relatively high isolation characteristic (where the isolation value is given in positive units).
A conventional circulator is typically a discrete device that can be mounted to a circuit board. As a discrete device, the conventional circulator does not provide an optimal form factor for high density electronics packaging.
It would therefore be desirable to provide a circulator that can be more easily integrated into an RF circuit and that has a smaller size than a conventional circulator.